>My days as of late have been a whole lotta weed, netflix, and nothing.
this would be the first thing I would change. Those things don't make for a fertile mind (don't @ me, you know it's true) In moderation, yes, but when they start to fill our days that is a clue (which you have clearly discovered, hence this post.) Also check in with yourself about the usual things - are you getting enough sleep/exercise/water/good food/hugs and tending to your surroundings (ie not taping leaves to dead trees and pretending it looks great or having a giant mound of candles and paper in the middle of your floor.)
A couple of new writing books that I have found very useful have been poetry craft journals, especially In the Palm of Your Hand: A Poet's Portable Workshop: The Poet's Portable Workshop and it's only $4 on kindle. It has really neat exercises that I think could help you focus your journaling and refine it, and because it's poetry, it's in really manageable doses.
I recommend this as a place to start: https://www.amazon.com/Good-Poems-Various-ebook/dp/B0031TZ8OU
Bonus points if you also get the audible version as most poems are meant to be heard and not read.
there's some chapters in this anthology focused on nature, it's one of my favs: https://www.amazon.com/Good-Poems-Various-ebook/dp/B0031TZ8OU/ref=sr_1_1?s=digital-text&ie=UTF8&qid=1501036318&sr=1-1&keywords=good+poems
I've written poetry since high school, but only recently gotten "serious" about it. I write every day (when it isn't finals season) on a wordpress blog, and I read a lot of poetry, pretty much by whoever I can find; recently this has been Keaton Henson, Warsan Shire, Aida Mitsuo, Michelle Smith, Tanaka Eris, John Keats, Robert Service, and lots of tanka and haiku by various authors. I think it's hard not to at least partially imitate someone you've read, even unconsciously.
I've also been reading the book "next word, better word" which has helped me a lot in terms of learning the formal elements of poetry and how they effect the more intangible aspects.
edit: spelling
I don't know is there an edition with every version of every poem (it'd have to be a hefty enough book)- but a good way to start off with Whitman is to get a copy of the 1855 Leaves of Grass (this one is good, unless you're actually some kinda poetry-loving millionaire, in which case you can just splurge on a real first edition.). After that, most "Collected Poems of...." books are based on the Deathbed edition, so any one of them will do. I think for a lot of his poems, the changes he made from book to book were minor enough, even though they do build up- especially in eg. Song of Myself (edited for about 30 years or something). But looking at the bookends gives you a good idea of how his writing changed overall, even if you don't see everything in between.
http://www.amazon.com/All-Us-Collected-Vintage-Contemporaries-ebook/dp/B00XST7S8C
Best I could get trying to find the poem I wanted to link specifically. If you go to the 'take a look inside' option, sift through a few pages until you find the poem "Luck"
It's one of my all time favorites. You can also check out however much that sample thing lets you.
There are some great suggestions here already, I'll third the Devil in the White City.
I'd also strongly recommend checking out <em>the Kingdom of Matthias.</em> It may not be a topic you'd think you'd be interested in, but it was one of the most readable, entertaining history books I've read. A fascinating story about little-known man who may have had a surprising level of influence on religion in America. It reads like a novel, but it's meticulously researched and makes no ridiculous claims for the sake of entertainment.